# A puzzle

A parallelepiped with edges 3,4,7, that can be divided in six equal pieces with three strata of 1,4,9 little cubes: a non-verbal proof of the fact that the sum of the squares of the first n integers is n(n+1)(2n+1)/6.

© matematita

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Numbers (Numbers)

Puzzles involving reconstruction of polyhedra (3D geometry)